This invention relates to an automatic telephone dialer and more particularly to such a dialer employing digital techniques.
Automatic telephone dialers of various types are well known in the art and have been widely used in fire and theft security systems. Many different types exist and, basically, function to dial a prerecorded telephone number and then send a notification of a fire or theft on the premises being monitored to the remote station or terminal.
Many of these devices employ prerecorded messages as well as telephone numbers on a magnetic tape associated with a transport. The units work in conjunction with existing telephone systems and are capable of dialing several different phone numbers and to supply information or emergency warnings regarding different types of panic situations such as fire, burglary, water or ph level. In any event, the use of such dialers in conjunction with magnetic tape also enables a prerecorded audible message to be transmitted to the remote location, such as a police station, firehouse and so on.
There also exists devices which are called digital dialers which are used to transmit a code over a telephone line. The remote station is also accessed by the unit which "dials" the remote station as indicated above and then transmits a particular code. The code is received at the remote location by a digital receiving device assoicated with the central location and which has a display consisting of appropriate digits to enable a user at the remote station to determine both the location and the nature of the emergency signal.
Thus, the digital dialer when activated, dials the telephone number of the central location and transmits to it a coded signal which is then decoded at the central location to indicate the subscriber and the type of alarm requested.
These digital dialers also perform other operations which were also implemented by the tape dialers. Thus such dialers may wait for a reply from the central station and disconnect if a reply is not received. These dialers will also disconnect and redial after the coded message is transmitted. Such dialers will attempt to dial the number until the message is acknowledged received and to further provide anti-jamming features to prevent someone from purposely tying up the telephone line.
In essence, such dialers do not transmit an audible signal such as the tape dialers, but do transmit an alarm code and as the tape dialers, can provide dial pulses for calling the remote station via a telephone line. There are many ways of programming the numbers such as the alarm code and the telephone numbers via such dialers. One technique employs a matrix which may mechanically store via a prewired system, a plurality of telephone numbers and the alarm codes. Each alarm code can be associated with a telephone number and hence, by means of patch cords or leads, one can then associate any alarm code with any particular number.
Certain dialers also use electronic memories in place of the matrix to store telephone numbers and alarm codes. These memories, of course, require a special programming or sequencing to control the memory. In any event, in employing such memories, there is a problem with the alarm code as to specify the particular type of alarm. Usually, a single dialer is connected to and monitors more than one zone. These zones may be different rooms in a building or different buildings.
Furthermore, the nature of the intrusion in each zone may be different. For example, one zone may be a fire zone, while the other zones may be burglar alarms and so on. In order to identify the zones at the remote location, it may be required that all fire alarms be represented by one number, all burglar alarms by another number and other conditions by an additional number. The dialer should also be capable of sending a test signal which may be still another number.
Such prior art dialers cannot progam the different alarm code number in the same location of memory for a particular zone. What is done is that an arbitary number such as 9, is programmed at a particular memory location associated with a particular zone. This digit of the memory location is inhibited prior to transmission over the telephone line and the proper digit representing a fire and so on is inserted.
Certain other systems, in order to circumvent this problem, employ an additional matrix whose main function is just to supply the alarm code. This matrix works in conjunction with a memory as well and is a hybrid system.
It is an object of the present invention to provide a digital dialer having the capability of programming any alarm code at a memory location at the same time as the telephone number is programmed. This therefore provides the user with greater flexibility, while providing an improved and more reliable dialing apparatus than those available in the prior art.